1. Field of the Invention
The present invention relates to an optical scanning type image display apparatus and method, in which light beams modulated in accordance with input image data are two-dimensionally scanned to display an image.
2. Description of the Related Art
In an image display apparatus using a light beam such as a laser beam, an image is displayed by two-dimensionally scanning a light beam while modulating the intensity of the light beam in accordance with input image data. Japanese Patent Application Kokai (Laid-Open) Publication No. 9-134135 (Patent Document 1) and Japanese Patent Application Kokai (Laid-Open) Publication No. 2003-43975 (Patent Document 2) disclose each an image display apparatus and method, in which a plurality of pixels is displayed at the same time by independently modulating a plurality of light beams. Since the simultaneous display of the plurality of pixels enables reduction of number of pixels to be displayed by each of the light beams, the intensity of the light beam can be modulated with a low modulation frequency.
The image display apparatus disclosed in the Patent Document 1 displays an image with use of a plurality of light beams in order to lower the modulation frequency of the light beams. The image display apparatus disclosed in the Patent Document 2, on the other hand, displays an image with use of a plurality of light beams in order to obtain a bright image. However, in the image display apparatus which is arranged so as to display different pixels at the same time with use of the respective light beams, a problem occurs that irregularities or inconsistencies in brightness appear in the displayed image, when there are variations in intensity between the light beams or when any of the light beams cannot be emitted due to the fact that any of a plurality of light emitting elements for outputting the light beams is faulty.